The present disclosure relates generally to formation evaluation. More specifically, the present disclosure relates to formation evaluation techniques, such as imaging of subsurface formations and fluids therein.
Exploration may be used to locate valuable hydrocarbons, such as oil and gas. Rigs are located at wellsites to drill wellbores and deploy tools downhole to locate subsurface reservoirs. Downhole tools, such as drilling tools, are advanced into the wellbore. Downhole tools, such as wireline tools, are deployed by a cable into the wellbore to collect subsurface samples for evaluation.
Downhole tools are often provided with logging devices, such as a nuclear magnetic resonance device to image subsurface formations. Downhole tools are also provided with sampling tools, such as probes, to draw samples of subsurface fluid into the downhole tool, and coring tools, such as axial and sidewall coring devices, to cut samples of subsurface formations. Examples of downhole tools are provided in U.S. Pat. Nos. 6,047,239 and 6,897,652.
Collected samples are captured in the downhole tool and retrieved to the surface. Samples are taken to labs for testing. Tests are performed on the samples to determine the presence of hydrocarbons. In some cases, core samples may be tested using nuclear magnetic resonance. Examples of testing are provided in U.S. Pat. Nos. 9,133,709, 8,499,856, 6,220,371 and 4,769,602.
Despite advancement in formation testing and sampling, there remains a need for techniques and tools capable of accurately evaluating subsurface formations.